Standardize usage of virtual/override/final in gin/

gin/shell/gin_main.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/i18n/icu_util.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 26 matching lines @@
   CHECK(base::GetCurrentDirectory(&module_base[0]));
   return module_base;
 }
 
 class GinShellRunnerDelegate : public ModuleRunnerDelegate {
  public:
   GinShellRunnerDelegate() : ModuleRunnerDelegate(GetModuleSearchPaths()) {
     AddBuiltinModule(Console::kModuleName, Console::GetModule);
   }
 
-  virtual void UnhandledException(ShellRunner* runner,
-                                  TryCatch& try_catch) override {
+  void UnhandledException(ShellRunner* runner, TryCatch& try_catch) override {
     ModuleRunnerDelegate::UnhandledException(runner, try_catch);
     LOG(ERROR) << try_catch.GetStackTrace();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GinShellRunnerDelegate);
 };
 
 }  // namespace
 }  // namespace gin
@@ skipping 20 matching lines @@
   CommandLine::StringVector args = CommandLine::ForCurrentProcess()->GetArgs();
   for (CommandLine::StringVector::const_iterator it = args.begin();
        it != args.end(); ++it) {
     base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
         gin::Run, runner.GetWeakPtr(), base::FilePath(*it)));
   }
 
   message_loop.RunUntilIdle();
   return 0;
 }